Rubber residues present harmful impacts on health and environment, besides wasting valuable and huge amounts of rubber. Biological recycling technique is focused here to minimize this problem. A comparison of the biodegradation effect caused by Bacillus subtilis, Pseudomonas aeruginosa, and Streptomyces sp., separately, on vulcanized SBR-rubber during 4 weeks is reported. The surface and molecular analyses were studied by FTIR-ATR, TGA, DSC, TC and SEM/EDS, in addition to the contact angle and crosslinking tests. B. subtilis, P. aeruginosa, and Streptomyces sp. evoked after 4 weeks a loss in v-SBR crosslinks by 17.15, 10.68 and 43.39% and also in the contact angle with water by 14.10, 12.86 and 15.71%, respectively., if compared to Control samples. FTIR findings indicate that the polymeric chain has been partially consumed causing C-C bonds scission indicating the biodegradation and bio-devulcanization phenomena. The bacterial strains caused a carbon loss by 9.15, 5.97 and 4.55% after one week and 16.09, 16.79 and 18.13% after four weeks for B. subtilis, P. aeruginosa, and Streptomyces sp. mediums, respectively. DSC and EDS results are also promising and highlighting Streptomyces sp. strain as the most effective biodegradative one as an alternative and natural mean of degrading vulcanized rubber residues.

The risks of environmental damage are inherent in oil activities, being a constant concern to our modern society. Among the remediation strategies, the biological one is safer and more inexpensive compared to physic‐chemicals approaches. Bioremediation can be enhanced using biodegradable polymers as coating materials of the nutrient release systems. However, some of these polymers can be improved using electromagnetic radiation, able to modify their properties, such as, molar mass, changing the materials physicochemical behavior. Thus, immobilizing urea in poly (butylene succinate) (PBS) matrix, producing a petroleum bioremediation tool was the primary goal in the paper herein. The composites were obtained by melting at 110 °C with subsequent application of gamma (γ) radiation at doses of 15, 25, 50, and 75 kGy. The obtained results allowed to infer that the increase of the γ radiation doses improved the immobilization, thus reducing the immediate urea release. Besides that, the preliminary biodegradation results showed that the highest rates of hydrocarbon reduction at the end of the analysis period were reached using the material irradiated at 25 kGy. These results are encouraging and proved that irradiated PBS‐urea systems could be used as oil spill disasters tool.

BACKGROUND: As population and fuel demand increase, many events of oil spills in the environment have been recorded. In order to restore these environments, several techniques have been proposed in the literature, especially in the field of bioremediation, with their main advantage being a low impact on the environment. In this work, poly(butylene succinate) microspheres containing urea were produced, representing a source of controlled release of nitrogen to the environment, promoting the biostimulation of the native microbiota of contaminated sites. Experiments were conducted based on the biostimulation of Pseudomonas aeruginosa and assessed the growth of the culture, the controlled release of urea, the substrate consumption and the toxicity of the microspheres using Artemia salina. RESULTS:The results showed that the double-emulsion methodology for urea encapsulation was efficient, with controlled release occurring up to 72 h. The urea-containing microspheres promoted microbial growth with higher protein synthesis (198.66 ∼g mL −1 ) in 72 h, from the consumption of glucose and urea, within the release limitations. The ecotoxicity of the urea-containing microspheres was tested with A. salina and the results showed a CL50 of 0.027 mg (10 mL) −1 , not recommending its use in the aquatic environment for this organism. CONCLUSIONS:The assays revealed that poly(butylene succinate) microspheres, both with urea and without this active ingredient, may not present toxicity to microorganisms such as P. aeruginosa and be toxic to more complex organisms such as A. salina.

Biodegradable polymers (e.g. poly(butylene succinate)-PBS) have been used in several sectors such as the environmental area, especially in bioremediation, in biological processes for conversion of pollutants into inorganic compounds. In this study, the foresight methodology for the use of biodegradable polymers, including PBS, reveals a publication rate of approximately 8.74 articles and 30.63 patents per year, between 2005 and 2019. However, the application of PBS, specifically, is still restricted to the environmental area, with only 3.0% of the 1484 works from this period. The results showed a more significant number of papers on the PBS application for synthesis, characterization, and application in the areas of Chemistry, Physics, and Pharmacy. In the area of bioremediation, only three studies related to PBS were found, revealing the lack of research and development to increase the contribution in the area of environmental recovery.

No abstract